What is a Shabbos Blech?

Blech is a Yiddish word referring to a large metal sheet designed to cover a stovetop to facilitate keeping food warm during the Jewish Sabbath. During Shabbat, lighting fires and active cooking are both prohibited. But in honor of the holy day of rest, it is also traditional to enjoy hot food. While from-scratch cooking is prohibited, halacha (Jewish law) does permit the warming of food that was prepared before Shabbat, or allowing partially cooked food to continue cooking on its own, provided certain guidelines are followed.

Over the centuries, observant Jews have devised ways to respect the complex laws related to warming food on Shabbat; utilizing a blech is designed to help mitigate halachic concerns about removing or returning pots to a flame, or adjusting the heat under the food.

A stovetop blech is a metal sheet, often made from aluminum, which is placed over a gas or electric stovetop before the Jewish Sabbath begins. Some designs cover just the cooktop, others cover the control knobs as well, to help prevent their accidental adjustment. Usually leaving one or two of the burners beneath the blech on low is sufficient for warming food placed on top of the blech.

A water blech (sometimes called an un-blech or kedeirah blech)is another option designed to address halachic issues related to placing food that has cooled back onto a blech. Some halachic authorities prefer water blechs, while others do not permit their use on Shabbat.

Some eschew the stovetop altogether, opting instead to warm their Sabbath food with an electric warming tray or slow cooker that is either plugged in before Shabbat, or attached to an automatic timer (Shabbat clock).

In response, BenTzion Davis, an Electronic Engineering Technician, set out to develop a safer electric hotplate specifically designed for extended Shabbat and Yom Tov use. Since fundraising via a successful Kisckstarter campaign, Davis' has obtained ETL certification, and put his design into production; it should be available in the US by March 2016; 220 Volt hotplates for the European and Israeli market are being designed as well.

Regardless of the type of blech one uses, there are important safety measures to take.

First and foremost, make sure you have both working fire detectors AND carbon monoxide monitors in your home. Both can go a long way toward protecting the family, whether a blech is in use or not!

Because the surface can get hot, children should be supervised if they're in the kitchen, and instructed never to touch the blech. Make sure cords are out of reach as well.

If you use extension cords, be sure to choose the correct type for both the outlet and appliance. And never try to run an appliance designed for use in Israel or Europe in America or vice versa, unless you have a proper transformer to handle the voltage differences.

Jason Broth, a longtime volunteer firefighter in Baltimore, cautions that the area around both stovetop and countertop electric blechs should always be kept clear; if you use the latter, the wires should also be checked before use. (Though some rabbis suggest partially covering pots on the blech with a cloth to prevent heat dissipation, this practice is a fire hazard, and should not be employed.)

Keep in mind too that from a food safety standpoint, bacteria thrive at temperatures between 40° and 140° F; so food that remains on a blech must stay heated beyond this temperature danger zone. Only eat food that has stayed hot on the blech; if it has cooled significantly, it is no longer safe to eat.

Example: Remember to put the kugel on the blech so it will be hot for Sabbath lunch.